Running a half marathon in under 2 hours: the MAS you need and the 10-week plan

What MAS do you need for a sub-2-hour half marathon?

You need a MAS of roughly 7.8 to 8.1 mph (12.5 to 13 km/h). A pace of 9:09 per mile is 84% of a 7.8 mph MAS and 81% of an 8.1 mph MAS, right in the middle of the half marathon pace range of the Running Workout plan, which runs from 82 to 85% of MAS. Without a target time, the plan sets that pace from your level: for a MAS between 7.5 and 9.3 mph (12 to 15 km/h), it is set at 81-84% of MAS.

The half marathon plan has one prerequisite: a run of at least 60 minutes in the last 90 days. If Running Workout finds none in your Garmin activities, the setup screen warns you and asks you to confirm your level, without blocking you. It also asks you to confirm your MAS, or to calculate it from a recent 10K time.

The half marathon plan sessions, week by week

The plan lasts 10 weeks, with two quality sessions and one long run each week. The first quality session works on MAS, the second on threshold (85 to 88% of MAS) and then half marathon pace; each starts with 15 minutes of easy running and 4 strides and ends with a 10-minute cool-down.

• — Weeks 1 to 3: 8 then 10 × 1 minute at 100% of MAS, then 12 × 30/30; threshold 2 × 8, 3 × 8 then 2 × 10 minutes; long run of 60, 65 then 60 minutes.
• — Weeks 4 to 6: 2- and 3-minute reps; 3 × 10 minutes at threshold, a first session at half marathon pace (2 × 3000 m), then 2 × 12 minutes at threshold; long runs of 70 and 75 minutes, the second finishing with 15 minutes at half marathon pace.
• — Weeks 7 and 8: 3 × 3000 m then 2 × 5000 m at half marathon pace, the key session of the plan; long runs of 85 then 108 minutes, with the last 20 then 28 minutes at half marathon pace.
• — Weeks 9 and 10: 3 × 1000 m then 6000 m at half marathon pace, a 70-minute long run; finally the taper, with 5 × 1 minute, 2 × 2000 m at half marathon pace, then the race.

The plan comes in two versions, chosen on the setup screen: three sessions a week (the two quality sessions and the long run) or four, adding an easy run of 35 to 45 minutes. With a MAS of 8.1 mph, threshold pace is between 8:26 and 8:44 min/mi.

What your 2-hour target time changes

If you enter 2 hours in the target time field on the setup screen, Running Workout sets the half marathon pace for the whole plan from that goal. Sessions at half marathon pace and long-run finishes then bracket 9:09 per mile, roughly 8:57 to 9:17 min/mi, whatever your MAS. The other paces (MAS, threshold, easy) are still calculated from your MAS.

This is where your MAS tells you whether the goal is realistic. With a MAS of 7.5 mph, 9:09 per mile is 88% of MAS, the fast end of your threshold pace, which the plan only asks you to hold for 2 × 12 minutes: the goal is very ambitious. At 8.1 mph, half marathon pace drops to 81% of MAS, well below threshold, and the plan works as designed.

Race day: the pacing instructions

The plan's race session starts a little slower than target pace: a 12-minute easy warm-up and 3 strides, the first 1.2 miles a notch below half marathon pace, then the remaining 11.9 miles at half marathon pace. Over the last 3 miles, you let go of whatever you have left.

With a MAS of 8.1 mph and a 2-hour target, the watch shows 9:17 to 9:31 min/mi over the first 1.2 miles, then 8:57 to 9:17 min/mi. Your AI assistant connected to Running Workout (Claude, ChatGPT or Gemini) sends this workout to Garmin Connect, dated on race day, and it syncs to the watch as a structured workout.

Frequently asked questions